Recently, NUI devices which input commands to a computer by using voices or motions of a user, rather than a method of inputting text or the like, have been developed and popularized.
However, currently popularized NUI devices merely identify motions of a user by tracking the locations of joints based on the motions of the user. Additionally, attempts have been made to interpret voices or motions of the user input via the NUI devices.
As one of the attempts, a dynamic time-warping technique has been proposed. That is, to identify a command meant by any motion, there is required a technology for verifying whether a motion previously defined for a corresponding command matches a current motion performed by a user. For this technology, a dynamic time-warping technique has been proposed.
According to a dynamic time-warping technique, when two sequences are given as M and N, computation corresponding to O(MN) is commonly performed. Additionally, when J is the number of all joints, computation corresponding to O(MNJ) must be performed. When it is assumed that the number of defined motions to be compared with a current motion performed by a user is K, computation corresponding to O(MNJK) must be performed. Such high computational complexity poses the problem of requiring extensive computing resources and a long period of time.
Furthermore, according to a dynamic time-warping technique, scaling must be performed to compare an input motion of a user with a predefined motion. In this case, since the size of a body varies depending on each user or the extent of detail of a motion operation must vary, a problem arises in that the motion of the user is recognized as an absolutely different motion.
In connection with this, Korean Patent Application Publication No. 10-2012-0000807 (published on Jan. 4, 2012), i.e., a prior art technical document, discloses a control device comprising a motion recognition unit configured to recognize a plurality of motions and a control unit configured to control a digital device based on the motions recognized by the motion recognition unit; wherein the control unit stops the control of the digital device based on the motions recognized by the motion recognition unit when the motion recognition unit recognizes a first one of the plurality of motions, and performs the control of the digital device based on the motions recognized by the motion recognition unit when a second one of the plurality of motions is recognized. That is, although the prior art technical document describes a technology for recognizing a motion and determining control based on the recognized motion, it does not disclose a method of effectively recognizing a motion, and thus the above-described problem is not yet overcome.
Accordingly, there is a need for a technology for overcoming the above-described problem.
Meanwhile, the above-described background technology corresponds to technical information that has been possessed by the present inventor in order to contrive the present invention or that has been acquired in the process of contriving the present invention, and cannot be necessarily viewed as a well-known technology that had been known to the public before the filing of the present invention.